The Medial Patellofemoral Ligament (MPFL) is the primary soft tissue restraint preventing the kneecap (patella) from dislocating toward the outside of the leg. When the MPFL tears, usually during a traumatic dislocation, the knee loses this restraint, leading to instability. For individuals with repeated kneecap dislocations (chronic patellar instability), MPFL reconstruction is a common surgical intervention. This procedure restores stability and function, but requires a careful evaluation of the commitment versus the long-term results.
The Need for MPFL Reconstruction
MPFL reconstruction addresses a knee joint that cannot keep the patella properly aligned. Recurrent patellofemoral instability, defined by multiple episodes of kneecap dislocation, is the primary indication for surgery. Since an initial dislocation tears the MPFL in almost all cases, the high risk of recurrence often necessitates surgery over non-surgical approaches.
Surgery is considered after conservative management (bracing and physical therapy) has failed. While injury can be traumatic, chronic instability is often linked to underlying anatomical factors that predispose the knee to dislocation. These factors include a shallow femoral groove (trochlear dysplasia) or a high-sitting kneecap (patella alta). In these situations, soft tissue repair corrects the mechanical failure.
The Commitment: Procedure and Rehabilitation Timeline
The procedure replaces the damaged ligament using a tendon graft, typically an autograft (from the patient) or an allograft (from a donor). The surgeon anchors the graft to the patella and femur, recreating the natural path and tension of the MPFL. While the surgery is generally an outpatient procedure, the true commitment is the post-operative recovery.
The initial recovery phase lasts about six weeks, focusing on protecting the graft, controlling pain, and restoring range of motion. Patients use crutches and a brace, with weight-bearing progressing gradually based on the surgeon’s protocol. Physical therapy initially focuses on ensuring the knee can fully straighten and achieving flexion goals necessary for normal walking.
The intensive rehabilitation period extends for many months, requiring consistent effort to regain strength and coordination. Advanced strengthening and functional training begin between three and six months post-surgery. A full return to high-impact activities, such as competitive sports, typically requires six to twelve months. This timeline reflects the biological process of the tendon graft maturing into a functional ligament.
Assessing Outcomes: Stability and Long-Term Function
The primary measure of success is the long-term stability of the kneecap. The procedure is highly effective in preventing future dislocations, with reported rates of recurrent instability often falling below 5% in high-quality studies.
Beyond preventing dislocation, the surgery significantly improves patient-reported outcomes, including pain reduction and overall quality of life. Many patients report high satisfaction, with some studies showing over 95% would choose the procedure again. Return-to-sport rates are encouraging, with many athletes resuming pre-injury activity levels, often around the six-month mark.
While outcomes are generally favorable, a small percentage of patients may experience complications, such as persistent stiffness or anterior knee pain. These issues are often manageable through continued physical therapy or minor subsequent procedures. The likelihood of adverse events is low compared to the success in restoring functional stability and improving quality of life.
Weighing Alternatives and Patient Selection Criteria
The decision to proceed with MPFL reconstruction follows a thorough consideration of non-operative options, such as specialized physical therapy focusing on quadriceps and hip strengthening, and patellar-stabilizing braces. These alternatives are preferred for patients who have experienced only a single dislocation or those with minimal anatomical risk factors. For patients with repeated instability, however, surgery offers a more definitive solution.
Patient selection is critical for a successful outcome. Surgeons identify appropriate candidates using criteria like a history of multiple dislocations and the presence of bony abnormalities visible on imaging. If the patient has a significant deformity, such as patella alta or severely shallow trochlear dysplasia, an isolated MPFL reconstruction may be insufficient. In these cases, the surgeon may recommend combination procedures, such as a tibial tubercle osteotomy (moving the patellar tendon attachment point) alongside the MPFL reconstruction, to ensure long-term stability. The surgery is a targeted intervention for specific mechanical failures, not a one-size-fits-all solution.